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<v ->I here, I show you a short list

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of some of the causes of neuropathic disease.

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I like to call this neuropathic osteoarthropathy

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but in some of the early books that we wrote

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there's a chapter entitled neuropathic arthropathy

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and I should never have used that term

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because neuropathic changes often begin

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in the subchondral bone and not in the joint.

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So a better term for this is neuropathic osteoarthropathy.

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With regard to diabetes, we recognize it most commonly

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about the foot, less commonly the ankle

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the need that is lower extremity, rarely upper extremity.

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And also it may involve the spine.

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I show you an example here

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of neuropathic osteoarthropathy

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I always think it looks a bit like OA with a vengeance.

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So we see more extensive bone fragmentation, subluxations.

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This is a classic location involving the LisFranc joint

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involving intertarsal joints as well.

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This is very, very characteristic you can see with MR.

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In addition to the morphologic changes

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low signal on T1, high signal on T2.

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Neuropathic findings can progress rapidly.

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So in this particular example,

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early on the major findings are marrow edema

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involving portions of the midfoot.

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One year later

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you can see the bone fragmentation that has occurred

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in this particular disease.

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A great finding, horrific finding

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for neuropathic osteoarthropathy

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unusual evulsion fractures of bone.

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So if you see, for example, particularly without an episode

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of severe trauma, an evulsion of the calcaneus

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by the Achilles tendon, that is diabetes

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until proven otherwise.

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That is a very important finding.

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And similarly unusual osteochondral fractures

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of joint surfaces is a manifestation

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of neuropathic osteoarthropathy.

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Diabetes can involve the spine.

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Here I show you in an example,

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the arrow indicating what this looked like.

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Initially, there were changes in the next disc space.

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Here we are.

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Three months later, no infection.

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You can see the disorganization occurring

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at that particular disco-vertebral junction.

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It looks like infection,

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and that can be a problem in differential diagnosis.

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Well, because of the occurrence of either

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neuropathic osteoarthropathy and infection,

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the American College of Radiology tried to come up

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with the scheme as to guide you

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as to what imaging studies should be ordered.

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And they came up with three variant scenarios.

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So let's quickly look at those.

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The first is a patient who comes in

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with suspected osteomyelitis

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of the foot based upon clinical findings.

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The initial imaging study

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in those patients should be radiography.

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You don't go to a cross-sectional technique.

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Now, if the radiographs reveals something significant

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you may have to go further from there.

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The second variant, variant two

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and you can see the full description over here.

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Is a patient who comes in with soft tissue swelling

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without an ulcer,

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the condition suspects osteomyelitis

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or early neuropathic osteoarthropathy.

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Additional imaging is generally employed.

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And typically following conventional radiography

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in variant two, it is MR are imaging

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either without IV contrast or with, and without IV contrast.

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And the third situation is the patient who comes

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in with soft issues, swelling with an ulcer

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and patient is suspected of osteomyelitis

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with or without neuropathic disease.

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Here again, you can start with conventional radiography

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but you need additional imaging.

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And most often we turn to MR

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with or without intravenous gadolinium

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in order to further evaluate it.

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So let me show you one scenario, variant three

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here's a patient who comes in soft tissue swelling,

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and ulcer visible clinically

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with clear neuropathic changes involving the foot.

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But there is a clinical suspicion here

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because of the ulcer for osteomyelitis.

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MR is indicated, was done in this case

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showing you in fact,

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the soft tissues swelling,

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the abscess, and ulcer, and involvement of bones.

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So this patient had both neuropathic disease,

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and osteomyelitis.

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Now those people who have written about

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the differentiation of neuropathic osteoarthropathy,

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and osteomyelitis have emphasized a sign

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seen on the T1 weighted images

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known as the ghost sign.

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Characteristic of infection,

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and not of neuropathic osteoarthropathy.

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So here's an example to show you how it works.

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We're dealing with a diabetic patient

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with extensive involvement of the midfoot.

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It could be neuropathic alone.

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All right.

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It could be neuropathic with infection.

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Let's get an MR.

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That's what would be suggested.

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The ghost sign indicates that when you look

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at the T1 weighted image of that area

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you don't see the subchondral bone plates

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or the cortices of the bone,

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the cortices of the bone very well.

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The bones kind of look all together like a ghost.

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And that is highly specific for infection.

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The fluid sensitive sequence are not

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where you will see the ghost sign,

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it's on the T1 rated image.

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So in this case, osteomyelitis with neuropathic involvement

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here's a second case, both with osteomyelitis.

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All right. And with a ghost sign.

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Again, you can't see the outlines of these bones here.

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All right?

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And indeed, in this case, also, the MR

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demonstrated a sinus tract.

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So this was osteomyelitis combined with neuropathic disease.

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And here's an example of neuropathic disease alone.

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The T1 weighted image.

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There is no ghost sign.

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You can see the surfaces

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although they're irregular of the bone

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the subluxations, look at the plantar flexion

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of the (indistinct).

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So this would be absent ghost sign.

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More characteristic of neuropathic disease.

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I just wanted to show you again

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an example of congenital insensitivity to pain syndromes.

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I've already shown you one during this course

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it's a variety of syndromes

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differing in their patterns of inheritance.

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And in my experience,

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one of the findings we see are these

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unusual osteochondral fractures.

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So when I see that in the absence of a good history

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of a significant injury,

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I think of neuropathic disease.